Growth suppression mediated by transfection of wild-type hMLH1 in human cancer cells expressing endogenous truncated hMLH1 protein.
Many genes that are frequently mutated in human cancer are known to be involved in the control of normal cellular proliferation. One of the genes involved in DNA mismatch repair is hMLH1, defective mutations of which are found in some familial and various sporadic cancers. Although the DNA mismatch repair activity of hMLH1 has been identified, other biological functions of hMLH1 have not been well investigated. To investigate the effect of wild-type hMLH1 in cellular proliferation, wild-type hMLH1 cDNA was introduced into human colorectal carcinoma cell line HCT116 and human gastric carcinoma cell line SNU-1, each containing a homozygous non-sense mutation at codon 252 and 226 in hMLH1, repectively. The hMLH1-transfected stable clones showed mRNA and protein expression of transfected hMLH1. Three in vitro cell growth experiments demonstrated that compared with parental and vector-transfected control counterparts, both hMLH1-transfected HCT116 and SNU-1 clones displayed: i) decreased cellular proliferation; ii) a significant decrease in the rate of DNA synthesis and iii) a dramatic reduction of anchorage-independence and the size of colonies in semisolid medium. In addition to DNA repair activity, these results suggest that hMLH1 may play a role in the negative regulation of HCT116 and SNU-1 cell growth.
Shin
K H
KH
Laboratory of Cell Biology, Cancer Research Center and Cancer Research Institute, Seoul National University, College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-799, Korea.
Han
H J
HJ
Park
J G
JG
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D002455:Cell Division; D003110:Colonic Neoplasms; D017931:DNA Primers; D004260:DNA Repair; D004261:DNA Replication; D018076:DNA, Complementary; D006801:Humans; D000070957:MutL Protein Homolog 1; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics*; D009687:Nuclear Proteins; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis; D013274:Stomach Neoplasms; D014162:Transfection; D014407:Tumor Cells, Cultured
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D017931:DNA Primers; D018076:DNA, Complementary; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D000070957:MutL Protein Homolog 1